Mastro, 87, and his wife Linda, 63, were arrested last month in a small town in the French Alps and face a 43-count U.S. indictment for bankruptcy fraud and money laundering.

Jim Frush, Mastro’s criminal attorney in Seattle, said a head injury that Mastro sustained in a fall at his home in Palm Desert in February 2011 may have affected his judgment.

“I’ve talked to enough people who’ve told me there is a night-and-day difference in Mike after the accident, the brain surgery and two weeks in intensive care," Frush said. "That suggests there may be an issue of competency in the case relative to his state of mind when he left the country and his state of mind today.”

“Both those areas are being considered by the French court,” Frush said. “I think there are some real issues whether Mike really understood the consequences of what he was doing when he left the country.”

Asked what role Linda Mastro might have played in the couple's decision to flee the country with $1.4 million in diamonds in June 2011, Frush said that Mastro was the one who made the decisions in the marriage. Before disappearing, the couple had been ordered by U.S. Bankruptcy Judge Marc Barreca to surrender two enormous diamond rings.

As to why the couple left the country, Frush said, “It’s speculation on my part but perhaps they had had enough stress, and the pressure to come back to Seattle was too much.”

The hearing this week in Lyon will address the couple's request for temporary release. So far, U.S. authorities have not requested the couple be extradited to the U.S., according to Frush. He is hopeful French authorities will release the Mastros. In addition to Michael Mastro’s age and health issues, Linda Mastro has been under medical care for nervous exhaustion, Frush said.

Mastro’s son, Michael K. Mastro, will arrive in France Tuesday to be with his father and stepmother during the court proceeding.

Frush also claimed that nothing has come of the Internal Revenue Service investigation of Mastro’s business activities.

“The federal authorities looking into the conduct of Mastro Properties. Based on what they know, they have not seen any criminal activity.”

The 43-count indictment for bankruptcy fraud and money laundering is tied to activities related to the personal bankruptcy, not to the business, he said.

While he does not know what property was in the couple’s possession when they were arrested, Frush confirmed the two diamond rings have not been sold.

Frush has not been able to talk to the Mastros since they've been detained in a French jail, but he has been in touch with the couple’s French lawyer, Thomas Terrier, who is fluent in English. Although Frush does not speak French, he can speak Nepalese, he said. Frush, an avid mountain climber, picked up the language during the three years he lived in Nepal as a younger man.